Field of the Invention
The present disclosure relates to a charging member, and a process cartridge and an electrophotographic image forming apparatus, hereinafter, also referred to as “electrophotographic apparatus”, including the charging member.
Description of the Related Art
One of methods of charging the surfaces of electrophotographic photosensitive members, hereinafter, also referred to as “photosensitive members”, is a contact electrical discharge process. In the contact electrical discharge process, voltage is applied to a charging member disposed on the photosensitive member to be in contact therewith and very small discharge is generated near the contact portion between the charging member and the photosensitive member to charge the surface of the photosensitive member.
A typical configuration of the charging member used in the contact electrical discharge process includes an electro-conductive elastic layer to sufficiently ensure the contact nip between the charging member and the photosensitive member. Unfortunately, the electro-conductive elastic layer often contains a relatively large amount of low molecular weight components. For this reason, these low molecular weight components may bleed to the surface of the charging member, and may adhere to the photosensitive member. To prevent bleed of the low molecular weight components to the surface of the charging member, a surface layer may be disposed on the electro-conductive elastic layer.
Japanese Patent Application Laid-Open No. 2001-173641 discloses an electro-conductive roll provided with an electro-conductive roll substrate containing a resinous material; and an inorganic oxide film as a bleed-preventing layer, which is formed by a sol-gel method, and covers a surface of the electro-conductive roll substrate.
In recent years, a further enhancement in durability has been required for electrophotographic image forming apparatuses. To meet this requirement, a charging member which exhibits stable charging performance for a long time is needed.